Effect of Mineralizers on Sintering Properties of MgO-Al₂O₃-SiO₂ Composite Ceramics

Abstract

MgO-Al₂O₃-SiO₂ composite ceramics are widely used in high-temperature filter materials, refractories, catalyst carrier materials and insulating materials because of their low coefficient of thermal expansion, good high-temperature stability and mechanical properties. In the process of preparing MgO-Al₂O₃-SiO₂ composite ceramics, it is more important to select a suitable mineralizer in order to effectively reduce the sintering temperature of MgO-Al₂O₃-SiO₂ composite ceramics and improve the properties of MgO-Al₂O₃-SiO₂ composite ceramics. In this experiment, 97 grade fused magnesia, Al₂O₃ powder and ferrosilicon ash powder were used as main raw materials. Meanwhile, Cr₂O₃ powder, ZrO₂ powder and TiO₂ powder were selected as mineralizers. MgO-Al₂O₃-SiO₂ composite ceramics were prepared by the semi-dry pressing method. The effects of different mineralizers on the sintering properties of MgO-Al₂O₃-SiO₂ composite ceramics were studied. The experimental results show that the addition of Cr₂O₃ powder cannot promote the sintering of MgO-Al₂O₃-SiO₂ composite ceramics and the addition of TiO₂ powder and TiO₂ powder can promote the sintering of MgO-Al₂O₃-SiO₂ composite ceramics. Moreover, the sintering performance of MgO-Al₂O₃-SiO₂ composite ceramics is better than that of MgO-Al₂O₃-SiO₂ powder. When the addition of ZrO₂ powder is 4%, it can promote the formation of periclase phase, refine grains and play a toughening effect, and the bending strength of MgO-Al₂O₃-SiO₂ composite ceramics reaches the maximum value of 19.3 MPa.

Keywords:

• MgO-Al₂O₃-SiO₂ composite ceramics
• sintering
• mineralizer
• bending strength